Brothers Andrew (drums and percussion) and Brad (vocals, guitar and keys) Barr, who have been members of the Slip and Surprise Me Mr. Davis, moved to Montreal after one of the brothers fell for a local waitress. Early on, Brad and neighbor Sarah Page (harp) could hear each other playing through the walls and struck up a musical friendship. Then, following the addition of Andres Vial (keys, pump organ and bass), the Barr Brothers were born. The folk quartet’s self-titled debut album (stream it below) came out in 2011. “The Barr Brothers are a different kind of folk group,” announced AllMusic, “bringing in unusual instrumentation and performing in a manner that draws the listener into a special musical world.” The Barr Brothers (above, playing “Even the Darkness Has Arms” on Late Show with David Letterman) released their second full-length, Sleeping Operator (stream it below), last month. And the good folks at Relix were impressed: “A product of both invention and intuition, the appropriately dubbed Sleeping Operator isn’t anything less than a dazzling delight.” See them headline The Bowery Ballroom tomorrow night. Bluesy folk singer-songwriter Leif Vollebekk, also from Montreal, opens the show.